A race condition occurs in computing when two or more processes or threads attempt to access shared resources simultaneously, leading to unpredictable outcomes. Imagine two people trying to fill a glass of water from the same tap at the same time; if they both turn the tap on, the glass might overflow or not fill properly. This situation can cause errors in programs, making them behave unexpectedly. To prevent race conditions, developers often use synchronization techniques, such as mutexes or semaphores. These tools help manage access to shared resources, ensuring that only one process can use the resource at a time, much like taking turns at the tap to fill the glass without spilling.